Industry requirements for thermal cycled adhesion of multiple layer hybrid circuits are becoming increasingly more demanding. The currently accepted industry practice is to use a silver/palladium ink or other conductive ink having a high silver content, which is printed on a dielectric substrate either in a single or double layer. A double layer is preferred because it reduces the chances of cracks or openings developing in the circuit, and increases the conductor thickness, thereby providing enhanced durability and performance. However, the resulting circuit has a limited thermal cycle life due to delamination or loss of adhesion of the conductor from the underlying dielectric layer.
It would be desirable to achieve improved adhesion of the printed circuit to the dielectric layer without substantially altering or complicating currently used manufacturing techniques. In particular, it would be highly desirable to achieve improved adhesion of the printed circuit to the substrate dielectric material without employing additional fabrication steps, and without requiring additional manufacturing equipment.